1. Field of the Invention
The present invention relates to an improvement of an exposure control device of a camera having auto-bracket photographing control means for permitting continuous photographing while automatically varying the exposure.
The auto-bracket (more exactly, auto-exposure bracket) is disclosed in U.S. Pat. No. 3,762,285 and Japanese Patent Application Laid-open No. 148437/1986 and it relates offsetting of the camera for the exposure of the camera (an exposure control value automatically calculated based on the brightness of an object and the film sensitivity in an automatic exposure mode, or the shutter speed and the stop value set by a user in a manual exposure mode). Briefly, the camera automatically changes the exposure value over several steps in a multi-frame photographing mode.
2. Related Background Art
An auto-bracket device is disclosed in U.S. Pat. No. 3,762,285 and Japanese Patent Application Laid-open No. 148437/1986.
In such a device, since the auto-bracket photographing mode can be selected irrespective of the camera mode, auto-bracket photography may be carried out in a mode not compatible to the auto-bracket photographing mode, for example, a bulb mode.
In the auto-bracket photographing mode, the exposure in each frame is automatically shifted, while in the bulb mode, the exposure is set by the user or operator and the bulb mode is not compatible with the auto-bracket mode. Thus, if both the auto-bracket mode and the bulb mode are simultaneously selected, the intended photography is not attained.
The prior art auto-bracket device provides no countermeasure where auto-bracket photography is not compatible with the setting of the camera, and in addition where the bulb mode and the auto-bracket mode are both set simultaneously.
More specifically, if a film is exhausted in the auto-bracket mode before a preset number of frames are photographed, and if new film is loaded to the camera and the rest of the auto-bracket mode photographing is commanded for, the newly loaded film, auto-bracket mode photography is carried out in spite of the fact that the object has changed during the film loading.
If the operator manually sets zero shift in the exposure for each frame in the auto-bracket mode photographing, a plurality of frames are photographed with the same exposure.